John Guest Speedfit 3/8 Inch OD Union Coupling, Push to Connect Plastic Plumbing Fitting, PP0412WD

Ideal for DIY pipe repair or installation, including hot and cold water systems but not steel or concealed systems
Fast and easy to install; Simply push to connect, with no need for tools
High-quality plastic offers corrosion resistance and long-lasting wear
One-piece construction means no parts to assemble
Among the easiest tools on the market for joining copper, CPVC and PEX (LDPE, MDPE, HDPE) tubing